禽脑脊髓炎病毒VR株的致病性研究

为探索禽脑脊髓炎病毒强毒VR株对SPF鸡的致病性,开展了不同接种途径和不同日龄SPF鸡的致病力试验。不同接种途径致病力试验结果表明,AEV VR株口服后不能引起发病;刺种、肌肉注射途径接种随着日龄增大,发病率降低;脑内注射途径接种可引起试验鸡全部发病。最小致病量试验结果显示,VR株脑内注射攻毒的最小致病量为10~(2.0) EID_(50)。不同日龄SPF鸡的致病力试验结果表明,随着试验鸡日龄的增大,其致病力略有差异,日龄越小,发病率越高。结果表明,AEV VR株脑内攻毒70日龄内SPF鸡的发病率为80%及以上,攻毒剂量为10~(4.0)EID_(50)。

Study on Pathogenicity of Avian Encephalomyelitis Virus Van Roekel Strain

To study the pathogenicity of avian encephalomyelitis virus Van Roekel (VR)strain in SPF chickens,pathogenicity test was conducted with SPF chickens of various ages by different routes of vaccina-tion.Pathogenicity test in SPF chickens by different routes of administration showed that chickens had no clinical signs after oral route vaccination,and with the growth of the chickens,the incidence rate decreased by wing-web and intramuscular inoculation,however,intracerebral injection led to 100% mortality.The minimum pathogenic dose was 102.0 EID50 by intracerebral route in the study of minimum amount of patho-genic test.The pathogenicity test with SPF chickens of various ages indicated that the younger the chicken is,the higher the morbidity is.Moreover,all the above serve to prove that the incidence rate of 80% or o-ver 80% was achieved by challenging with virulent AEV VR strain to SPF chickens less than 70 day-old by intracerebral route of inoculation,with the challenge dose of 104.0 EID50 .